This invention relates to aircraft brakes wherein brake actuation and release are achieved by electrical control as opposed to hydraulic control. Hydraulically controlled aircraft braking systems are, of course, well known in the prior art.
More particularly, this invention provides a brake wherein a plurality of electric torque motors effect wheel braking through reciprocating control means which operate to compress a multi-disk stack of frictional braking elements.
Electrically actuated aircraft brakes of various configurations are already known as exemplified in U.S. Pat. Nos. 4,381,049; 4,432,440; 4,542,809; and 4,567,967. All of these are by Richard L. Crossman and assigned to Goodyear Aerospace Corporation, Akron, Ohio. The inventions described and illustrated in the above-referenced patents pertain to reciprocating control means in various configurations of a ball-screw drive wherein electric torque motors responding to an electrical control signal from the pilot effect rotation of a ring gear member which interacts through a plurality of balls to drive an axially positioned and linearly moving ram member into contacting engagement with a brake pressure plate. The brake pressure plate effects compression of a brake disk stack to stop a rotating wheel. The ball-screw drive mechanism is in an annular configuration about the axis of rotation of the wheel and applies a braking pressure force in the axial direction on the pressure plate which is an annular disk at the inboard end of the brake disk stack of frictional braking elements.
Another configuration of an electrically actuated brake is described in U.S. Pat. No. 4,596,316 to R. L. Crossman and also assigned to Goodyear Aerospace Corporation. According to this patent, a reciprocating control means is in the form of a roller screw drive wherein a ring gear member interacts through a plurality of roller screws to drive a ram member into engagement with the brake pressure plate to effect compression of the brake disk stack for braking action. A plurality of electric torque motors and their associated pinions drive a ring gear into rotation and the plurality of roller screws effect linear axial movement of the ram member.
Nut-and-screw drives, which convert rotary input motion to a linear output motion, are already known as exemplified in U.S. Pat. No. 3,595,094 assigned to Aktiebolaget Svenska Kullagerfabriken; U.S. Pat. No. 4,576,057 assigned to Illinois Tool Works, Inc.; and U.S. Pat. No. 4,037,893 assigned to La Technique Integrale. La Technique Integrale of Chambery, France is a primary producer of such drive mechanisms and these are marketed in the U.S. by SKF International under the tradename TRANSROL.
This invention is directed to a configuration of a roller screw drive of the planetary or recirculating roller screw type wherein each electric torque motor of a plurality of such motors drives an individual roller screw mechanism through a right-angle gearhead and the linear moving member of the roller screw drive mechanism makes contacting engagement with the brake pressure plate to effect braking action of a rotating aircraft wheel. The torque motors and their associated gearheads and roller screw drives are mounted in various configurations and in a balanced arrangement about the axis of rotation of the wheel and brake assembly.
The embodiments of the invention described and claimed herein are directed to the arrangement of torque motors and the reciprocating control means and do not elaborate upon the means by which the pilot of the aircraft may apply the electrical control signals to the torque motors which drive the reciprocating control means. Any type of electric brake controller which regulates the direction of current flow to the torque motors to achieve either brake application or brake release may be applied to the invention. A particular one such electronic controller is described in U.S. Pat. No. 4,568,863 to Edgar J. Ruof and assigned to Goodyear Aerospace Corporation, Akron, Ohio.